Attachment for doors



Oct. 8, 1935. w. T. KNIESNER ATTACHMENT FOR DOORS 2 Sheets-Sheet 1 Filed Aug. 19, 1955 INVENTOR .h z'lliam fKntesner BY M A MO E M ATTORNEYS 2 Sheets-Sheet 2 Filed Aug. 19, 1953 KNVENTOR William 1'. K71 iesner ATTORNEYS Lil Patented Oct. 8, 1935 UNITED STATES FATENT OFFICE 22 Claims.

This invention relates to attachments for doors of the kind which permit an occupant of a room or the like, in response to a ring or other call at the door, to peek out and inspect the applicant for admission.

One of the objects of this. invention is to provide a simple, inexpensive but thoroughly rugged and practical construction of the above-mentioned character. Another object of this invention is to provide a construction of this kind which will be simple and inexpensive to manufacture, capable of rapid assembly, capable also of ease of installation, and capable of simple and reliable manual manipulation or operation thereof. Another object is to provide a construction of the above-mentioned character that will be well adapted to meet the varying conditions of practical usev Another object is to provide a construction of the above-mentioned kind in which reliability of operation is achieved in a thoroughly practical and simple way, also one which will be foolproof, and in which possibility of its getting out of order and needing repair or replacement is reduced to a minimum. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying .drawings, in which are shown several of the various possible embodiments of my invention,

Figure l is a front elevation showing the device installed in a door, the door being only fragmentarily shown, however;

Figure 2 is a horizontal sectional view, as seen along the line 22 of Figure 1 showing certain structural interrelations of certain of the parts;

Figure 3 is an elevation like that of Figure 1 but it shows the device in operate-d condition;

Figure 4 is a horizontal sectional view like that of Figure 2 showing another form of my invention;

Figure 5 is a plan view of a transparent barrier or closure member;

Figure 6 is a similar plan view of an opaque barrier or closure member;

Figure '7 is a front elevation like that of Figure 1 showing the parts of my other embodiment in one position of their operation, and

Figure 8 is a similar View showing the parts in another selectable position of operation.

Similar reference characters refer to similar parts throughout the several views of the drawings.

As conducive to a clearer understanding of certain aspects of my invention, it might at this point he noted that various attempts have hereto- 5 fore been made to provide doors with attachable devices whereby an opening in the door may be at will uncovered to permit sighting therethrough, but such prior attempts are characterized by numerous deficiencies and defects. For example, 10 they are devoid of ease or simplicity of manual actuation and frequently cumbersome manipulation of latches and the like has to be resorted to in the attempt to achieve an opening of the devices; also they are complicated to manufacture, are unreliable in operation, and, where latches or bolts are employed, they are undependable either because of the undependability of the corresponding construction or the reliance upon the operator to insure that the latch or bolt is in proper position. Furthermore, prior devices are devoid of ease or simplicity of control. One of the dominant aims of this invention is to do away with such disadvantages, complications and deficiencies.

Referring now first to Figures 1 and 2, there is shown at a portion of a door, such as a portion of the panel of a door and in this panel I provide an opening 2 i, preferably circular; into this opening is fitted the device of my invention.

The latter includes a cylindrical frame 22, preferably made of any suitable metal, having an outside diameter sufficient freely to pass through the opening El and having an inside diameter on the order of several inches, for example, adequately to serve the purpose of the device. The frame 22 may be secured to the door 26 in any suitable way and preferably and illustratively the frame 22 is provided with a peripheral flange 23 adapted to abut against the outside face of the door 20, about the opening 2 5, while the outer cylindrical portion of the frame 253 is threaded as at 24 to receive a threaded ring or collar 25 whereby the door as may be securely clamped between the flange 23 and the threaded collar 25, thus securely holding the frame 22 and its related parts in position.

The opening 26 in the frame 22 is closed by a plate-like closure 21, preferably opaque and conveniently made of metal, and preferably circular, having a diameter equal to or preferably less than the outsidediameter of the cylindrical frame 22; the closure 21 (see Figure 1) being upon the inside of the door, is pivoted to the frame 22 by a suitable stud, rivet, screw, or the like, in-

dicated at 28, the latter part being preferably countersunk in any suitable manner. Preferably the pivot 28 is positioned on the upper half of the frame 22 and preferably on the vertical diameter of the latter.

Spaced about 90 from the pivot 28 (in counterclockwise direction as viewed in Figure 1), the frame 22 is provided with a pivotal support, preferably taking the form of a post or stud 29, adapted to carry a suitable pin, rivet, screw, or the like, indicated at 3B, for pivotally supporting a link 35 which is more clearly described hereinafter. The post or stud 29 is preferably of a height (see Figure 2) slightly greater than the thickness of the closure 2! and its upper face is made of as large an expanse as possible and the head of the screw, pin, rivet, or stud 3B is likewise made preferably of substantial area so that the link 3! is not only dependably pivoted to the frame but also, by these relatively large surface areas, held in a plane extending at right angles to the axis of the pin 35, whereby the link 3!, when it swings as hereinafter described, is dependably held from wabbling and is made to move and be retained within its own plane.

Spaced substantially 90 (in counter-clock wise directionFigure 1) from the pivoting pin 28, the disk-like closure 21 is cut-out, as at 21 in order within this cut-out portion 21 freely to accommodate the post or stud when the member 21 is in normal or closing position.

At substantially the center portion of the disklike closure 2?, the latter is provided with a stepped boss or stud 32 preferably formed integrally therewith; the lower step 32 of the boss 32 is of a thickness or axial dimension slightly in excess of the thickness of the link 3i and its upper face provides a large-diametered bearing face or surface against which rests a lever 33, the lever being suitably apertured to be re ceived about and to thus pivot about the upper step 32 of the boss 32; a suitable headed pin, rivet, screw, stud, or the like, indicated at 34 and preferably having a large-diametered head, is in rigid connection with the boss 32 and 0verhangs the upper face of the lever 33, the latter being thus free to swing about the boss 32 but held against wabbling by the large opposed bearing faces of the head of the stud 34 and of the lower step 32 of the boss 32; thus the lever 33, when it swings about the axis of the stud 34, is dependably maintained at all times in its own plane, a plane at right angles to the axis of the stud 34.

The right-hand ends of the link 32 and lever 33 are pivotally connected in any suitable manner, but where I employ a construction like that above described, in which the link and lever are pivoted so as to limit wabbling thereof, I may, due to the coaction of these features, pivotally connectthese two par s, as is indicated in Figures 1 and 2. One of the parts, such as the lever 33, is provided with a hole 33 while the other member, such as the link 3!, is provided with a stud 35 which may be integrally formed therewith or otherwise secured thereto. In assembly, therefore, the right-hand ends of the lever 33 and link 35 need merely be overlapped so that the stud on one enters the hole in the other, the assembly of these parts to the closure 2'! and to the frame 22 preventing this pivotal connection from coming apart.

Referring now to Figure 1, the lever 33 will be seen to be preferably in the shape of a bell crank lever, its left-hand arm carrying a knob or handle 35 (see also Figure 2), whereby the lever 33 may be grasped by the fingers of the hand and operated. The link 3| is somewhat curved and the parts are so proportioned, substantially as is indicated in Figure i, that with the closure member 27 in closing position, the axis of the pivot 34 for the lever 33 is positioned slightly above a straight line connecting the axis 39 about which the link 3! pivots and the axis 3% about which the link SI and lever 33 are relatively swingable. Moreover, the lever 33 is extended upwardly, as at 33* (Figure l), substantially concentrically about its pivot 34, so that the portion 33 well overlaps the central portion of the link 3i when the parts are in normal position.

With the parts in normal position, the closure member 34 cannot be forced from the exterior of the door 2! Any forces applied to the closure 21 in the direction of its axis (for example, upwardly as viewed in Figure 2) are resisted not only by the pivotal connection 28 of the closure 21 to the frame 22 but also by the lever 33, link 3|, and the pivotal connection of the latter, as by the stud 36, to the post 29. The link 3| dependably overlaps the closure 21, being reliably held in such overlapping position by particularly the portion 33 of the lever 33, as well as by the right-hand arm of the latter,

Any forces applied to the closure member 2'! tending to swing the latter about the pivot 28 are applied to no avail. Any such force tending to swing the closure 21 in clockwise direction, as viewed in Figure 1, are dependably resisted by the abutting of the central portion of the link (it the portion (see Figure 2) of the boss 32, it being noted that, because of the relation of the pivot points above noted, any such force would have to tend to rotate the link 3! in clockwise direction. Moreover, the link 3i acts as a compression member and such forces are dependably taken up by the pivot 39.

Any forces tending to rotate the closure member 21 in counter-clockwise direction are transmitted to the linkages through the pivot 34 of the lever 33, but that pivot being above the line joining the pivots 3E? and 35 any such force acts in a direction to tend to rotate the lever 33 and link 3| in clockwise direction, but the abutting of link 3! against the boss 32 dependably precludes such rotation. The link 3| now acts as a tension member, being anchored by the pivot 36.

Thus, a secure and reliable closure of the opening N is maintained.

When it is desired to uncover the opening 26, the operator grasps the handle 35 and it will be noted that handle can be rotated only in one direction, namely, in a counter-clockwise direction with respect to the pivot 34. As such rotation proceeds, a complex but efiicient motion of translation of the lever 33, accompanied by a swinging of the closure member El about its pivot 28 takes place. The initial movement is such that lever 33 begins a swinging movement of the member 2'5 with the pivot 31 acting normally as a stationary fulcrum but thereupon the link 3! begins to swing in counter-clockwise direction, lever 33 continuing to operate upon the closure 2? but now through a fulcrum (pivot 3la) which progressively moves upwardly as the link 39 swings in counter-clockwise direction, the parts approaching a position like that shown in Figure 3, the opening 26 being completely uncovered at that stage.

Furthermore, if desired, the movement of the closure 2! beyond the position shown in Figure 3 may be prevented and in such case I provide the extreme end of the link 3| with an upwardly projecting stud 3% (Figures 1 and 3) so positioned that, by the time the link 3! and lever 33 have relatively rotated to the positions shown in Figure 3, the lever 33 is brought into engagement with the stud 3|, thus preventing further flexing of the linkages in that direction.

In effect, the mechanism constitutes a system of linkages, of which the frame 22 may be considered to be one link, link 3| another, one arm of lever 33 constituting a third link, and closure member 27 constituting the fourth link, the linkage being collapsible into the relation of the parts shown in Figure 1 but with results as outlined above and being expansible into the positions shown in Figure 3, resulting in uncovering of the opening 26. Furthermore, where the parts are loosely pivoted or loosely pivotally connected, as is preferably the case, I may and preferably do utilize the weight of the closure 21 to effect a collapsing of the system of linkages above described. In any event, however, a simple and foolproof construction is achieved, capable of speedy and reliable and foolproof manipulation. There are no latches or bolts to get out of order or to be concerned with and yet excellent security is achieved.

Under certain circumstances of practical requirement, I may employ a construction like that shown in Figures 5-8 in which all of the parts heretofore described in connection with Figures 1-3 are duplicated but made to coact with other features advantageous under such circumstances. Referring now first to Figure 4, the closure member 21 hereinbefore described will again be seen to be present, similarly mounted and actuated as above described, but the pivot pin or stud 28 is of greater length and the post 29 is also of greater length; this difference in these dimensions is for the purpose of accommodating underneath the opaque closure 21 a transparent closure member generally indicated at 36 and comprising a metal frame 31, suitably bezelled or otherwise recessed as at 5. 8 to receive therein and hold a suitable transparent disk 39, made of glass, celluloid, mica, non-shatterable glass, or the like. The metal frame 3'! is ring-shaped (see Figure 5), being apertured as at 31* to receive the pivoting stud 253 and being also cut out or recessed as at Sl so as to make way for the post 29 that carries the pivoting stud 2 8 of the link 3!.

The closure 2! (Figure 6) has secured thereto integrally formed therewith an arcuate rib 49 positioned and dimensioned substantially as is indicated in Figure 6. This rib 49 is, moreover, on that face of the closure 2? that faces toward the transparent closure 36, and in thickness (see Figure 4) it is of about the same dimension as is so much of the metal frame 31 that projects beyond the plane of the adjacent face of the transparent disk, 39.

With the parts in closing position, the lefthand end of the rib til, as viewed in Figures 4 and 6, engages against the left-hand interior portion of the metal frame 37 of the transparent closure member 36, and inasmuch as the member 2? is securely held against being swung about its pivot 23, as will be clear from what hasbeen said above in connection with Figures l3, member 36 is precluded from being moved about the pivot 28 inasmuch as the post 29 (Figure 4) extends to one side of the left-hand portion of the frame 31 and the rib 40 extends against and engages the other side of the left-hand portion of the metal frame 37.

If it is now desired to make an observation through the door without physically exposing the eye through the opening 26 in the frame 22, the operator grasps the handle 35 and begins to rotate the lever 33, achieving the mechanical advantage and actuation as above described, but he halts the rotation of the lever 35 at a position of the closure member 21 as is shown in Figure 7, from which it will be seen that the transparent member 36 remains in closing position while the opaque member 27 has been moved to a sufficient extent to uncover the glass or transparent part 39 sufliciently to permit the free use of the eye in making the observation desired. In this position of the parts, the rib 40 on the inside face of the closure 21 has moved away from the inside edge of the left-hand portion of the frame 3? and has approached or has contacted the inside edge of the right-hand portion of the metal frame 31, all as clearly appears in Figure 7.

If no communication is desired to be made through the opening 26, the handle 35 is released or is rotated in reverse direction, thus restoring the parts to normal or closing position, transparent closure member being again held between the post 29 and the rib it as above described.

However, should it be desired to speak through the opening 25 or to pass small articles or objects therethrough, the operator continues the rotation of the handle 35 beyond the position of the parts shown in Figure '7, and such continued rotation of the closure 2? causes the latter to swing the transparent closure 35 upwardly with it, due to the engagement of the rib 40 now against the inside edge of the right-hand portion of the frame 3?, as is clearly shown in Figure 8. Thus, the opening 38 is completely uncovered.

ihe swinging movement into or beyond the position shown in Figure 8 may be halted at any desired point either manually or by the means, such as the member 3! of Figure 3, above described. As was described above in connection with Figure 3, such a halting may under some circumstances be desirable, particularly if it is preferred to prevent the closure member 27 from too great an arc of swing or from such a great arc of swing that its center of mass passes from the right-hand side of the pivot 23 to the left-hand side thereof. With the arrangement of Figures 58, however, a wider arc of swing of the opaque closure member 21 may be made to take place inasmuch as, where such a limitation of the arc of swing is desired to be utilized, the center of mass of both opaque and transparent closures 2'! and 3'5, res ectively, are to be borne in mind, and with the anguiar displacement between these two parts, as shown in Figure 8, a greater angle of swing may be accorded the member 27, while still maintaining the center of mass of the parts 21 and 3? to the right-hand side of the axis 28.

Referring still to Figure 8, if the operator now desires to bring about a closure of the opening 2 he may swing the handle 35 in clockwise direction or may allow the weight of the parts 37 and to return them respectively to closing position. In either case the rib til on the opaque closure ultimately disengages from the righthand portion of the frame 3'? and comes into engagement with the left-hand portion thereof, thus not only insuring the dependable return of the transparent closure 36 but also restoring the latter to its normal position where it is held immovable between the immovable post 29 and the normally immovable rib 46.

It will thus be seen that there has been provided in this invention a construction in which the various objects hereinbefore noted, as well as many thoroughly practical advantages, are successfully achieved. It will be seen that the construction is of inexpensive manufacture, simple to manipulate, is foolproof, is characterized by great facility in manual operation and, moreover, is thoroughly secure and dependable. Moreover, it will be noted that the many advantages of the construction are achieved without detracting from the possibility of ease and speed of installation in a door inasmuch as, viewing Figures 1, 2 or 4, for example, the various movable parts will be seen to fall within the outside diameter of the cylindrical frame 22 and thus they are readily passed through the opening in the door 28, the ring 25 slipped over them and screwed home. Moreover, it will be seen that the construction is well adapted to meet the hard and varying conditions of practical use.

Under certain circumstances I may prefer to avoid limiting the movement of the closure member 2! to a position such that its weight falls to the right of the pivot 23 and in such case I may either entirely omit the projection 35 (see Figure 3) or I may space it farther away from the pivot 3 i the spacing being indicated in Figures '7 and 8, so that the closure plate El can continue its swing to carry its weight to the left of pivot 28, in which case the weight of the member 2%: acts to hold the links 3! and 33 against continued flexing and the links thereupon act to hold the closure plate 21 in open position. This action and construction is substantially that of Figures 7 and 8, disregarding the member 35.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:-

1. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, and a link pivoted to said frame member at one end thereof and to said lever at the other end thereof, said last-mentioned end of said lever forming a movable fulcrum for said operating lever.

2. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, two pivotally connected links, one link being pivoted to said frame member and the other link being pivoted to said closure member, and means for manually rotating one of said links about its pivot.

3. Inconstruction of the character described, in combination, an apertured frame member adapt-ed to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, a pivot on said frame member and positioned at a point in the arc of swing of said closure member, a link extending across the face of said closure member and pivotally supported by said pivot, a pivot on said closure member, a link pivotally supported by said second-mentioned pivot and extending in the same direction as said first-mentioned link, said links being pivotally connected at their free ends, and means for manually changing the angle between said links and thereby effecting swinging of said closure member about its pivot.

4. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, a pivot on said frame member and positioned at a point in the arc of swing of said closure member, a link extending across the face of said closure member and pivotally supported by said pivot, a pivot on said closure member, a link pivotally supported by said second-mentioned pivot and extending in the same direction as said firstmentioned link, said links being pivotally connected at their free ends, said second-mentioned pivot being so alined with respect to the firstmentioned pivot and the pivotal connection of said links that a force applied to said closure member and tending to swing it about its pivot is prevented from changing the angular relation between said links.

5. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, a pivot on said frame member and positioned at a point in the arc of swing of said closure member, a link extending across the face of said closure member and pivotally supported by said pivot, a pivot on said closure member, a link pivotally supported by said second-mentioned pivot and extending in the same direction as said firstmentioned link, said links being pivotally connected at their free ends, means for manually effecting change in the angular relation between said links and thereby effect opening movement of said closure member about its pivot, and means for limiting the change in angular relation between said links and thereby limiting the opening movement of said closure member.

6. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, an operating lever pivoted to said closure member at substantially the center thereof, a pivot on said frame member and positioned at a point in the arc of swing of said closure member, a link extending across the face of said closure member and pivotally supported by said pivot, a pivot on said closure member, a link pivotally supported by said second-mentioned pivot and extending in the same direction as said firstmentioned link, said links being pivotally connected at their free end, means for manually affecting change in the angular relation between said links and thereby effect opening movement of said closure member about its pivot, and means for limiting the opening movement of said closure member.

'7. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, a lever mechanism connecting said two members, said mechanism normally assuming a dead center relation to prevent opening movement of said closure member, and manually operable means for moving said mechanism out of dead center relation.

8. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, said members functioning as two pivotally connected links, and two pivotally connected links each pivoted to one of said members and forming therewith a four-bar linkage, said links being proportioned and the pivots thereof so related that said second-mentioned two links, when holding a certain angular relation, hold said closure member in closing position and when given a different angular relation effect positioning of said closure member in open position.

9. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, said members functioning as two pivotally connected links, and two pivotally connected links each pivoted to one of said members and forming therewith a four-bar linkage, said links being proportioned and the pivots thereof so related that said second-mentioned two links, when holding a certain angular relation, hold said closure member in closing position and when given a different angular relation effect positioning of said closure member in open position, said second-mentioned two links, when in said firstmentioned angular relation, assuming a dead center position for preventing movement of said closure member out of closing position.

10. In construction of the character described, L1 combination, a four-bar linkage comprising a frame member having an opening therein and adapted to be set into the opening in a door or the like, a closure member forming the second link and pivotally connected to said frame member and two pivotally connected links, each pivoted to one of said members, for controlling the swinging movement of said closure member relative to said frame member.

11. In construction of the character described, in combination, a four-bar linkage comprising a frame member having an opening therein and adapted to be set into the opening in a door or the like, a closure member forming the second link and pivotally connected to said frame member and two pivotally connected links, each pivoted to one of said members, for controlling the swinging movement of said closure member relative to said frame member, three of the pivots of said linkage assuming substantially a straightline relation for preventing movement of said closure member relative to said frame member.

12. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, said parts being pivoted so that the closure member swings in its own plane, and means for operating said closure member, said means comprising a link pivoted to said frame member and overlapping said closure member and a link pivoted to said closure member and pivotally connected to said first-mentioned link.

13. In construction of the character described, in combination, an aperture-d frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, said parts being pivoted so that the closure member swings in its own plane, and means for operating said closure member, said means comprising a link pivoted to said frame 5 member and overlapping said closure member and a link pivoted to said closure member and pivotally connected to said first-mentioned link, said first-mentioned link, in overlapping said closure member resisting swinging of said closure member transversely to its plane, and said second-mentioned link overlapping said first-mentioned link and thereby resisting swinging of said first mentioned link transversely to its plane.

i l. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, a bell crank lever pivotally connected to said closure member and having a handle at the free end of one of its arms, and means whereby the free end of the other arm of said lever reacts against said frame member and rotation of said bell crank lever is thereby caused to effect motion of translation of its pivot and hence of said closure member.

15. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, a lever having a handle thereon, said lever being connected to said closure member so that the latter forms the load to be moved by said lever, and means whereby the fulcrum end of said lever reacts against said frame member so that movement of said lever effects movement of said closure member about its pivot.

16. In construction of the character described, in combination, a frame member, an opaque closure member pivoted thereto, a transparent 010- sure member interposed therebetween, and connections between said two closure members whereby movement of the opaque closure member in opening direction effects movement of said transparent closure member only after a certain uncovering movement of said opaque member has taken place.

17. In construction of the character described, in combination, a frame member, an opaque closure member pivoted thereto, a transparent 010- sure member interposed therebetween, manually operable means connected to said opaque closure member and said frame member adapted on operation to effect an opening movement of said opaque member, and lost motion connection means for effecting uncovering movement of said transparent member only after a certain movement in opening direction of said opaque member.

18. In construction of the character described, in combination, an apertured frame member adapt-ed to be secured into the opening of a door or the like, an opaque closure member for said aperture, a transparent closure member interposed therebetween, and manually operable mechanism for successively moving said opaque closure member and said transparent closure member into aperture-uncovering positions, said mechanism comprising a member capable of being grasped by the hand and moved, means ineluding said opaque member for giving said member a relatively fixed path of movement so that said opaque member is moved into aperture-uncovering position when said member is moved in one direction along its path, and means effecting opening movement of said transparent closure member only throughout a later portion of the path of movement of said member when moved in said one direction.

19. In construction of the character described, in combination, an apertured frame member adapted to be secured in the opening of a door or the like, a closure member pivoted to said frame member, a lever, means pivoting and securing said lever to said closure member, and a link having pivotal connection with said frame member and said lever, one of said pivotal connections being held in operative relation by said lever.

20. In construction of the character described, in combination, a four-bar linkage comprising a frame member having an opening therein and adapted to be set into the opening in a door or the like, a closure member forming the second link and pivotally connected to said frame member at a point such that the weight of said closure member acts to move said closure member into position to close said opening in said frame member, and two pivotally connected links, each pivoted to one of said members, substantially folded one upon the other under the action of the weight of said closure member but adapted, when given substantially an unfolding movement, to swing said closure member in a direction to uncover the opening in said frame member.

aoiasiee 21. In construction of the character described, in combination, a four-bar linkage comprising a frame member having an opening therein and adapted to be set into the opening in a door or the like, a closure member forming the second link and pivotally connected to said frame member at a point such that the weight of said closure member acts to move said closure member into position to close said opening in said frame member, and two pivotally connected links, each pivoted to one of said members, substantially folded one upon the other under the action of the weight of said closure member and having the three pivots thereof substantially in a straightline relation for preventing movement of said closure member relative to said frame member.

22. In construction of the character described, in combination, a member having an opening therein, a closure member pivoted to said firstmentioned member for closing said opening, and

WILLIAM T. KNIESNER. 

